Semi-solid material formation within a cold chamber shot sleeve

ABSTRACT

A method and apparatus is disclosed for the preparation of a semi-solid material in a mixing sleeve of a casting apparatus, the semi-solid material formed from a molten material after a mixing and a cooling thereof in the mixing sleeve wherein a handling of the semi-solid material is minimized.

FIELD OF THE INVENTION

The invention relates to the formation of a semi-solid material and more particularly to a method and apparatus for the preparation of a semi-solid material in a mixing sleeve of a casting apparatus, wherein the semi-solid material is formed from a molten material after a mixing and a cooling thereof in the mixing sleeve and prior to being transferred to the shot sleeve.

BACKGROUND OF THE INVENTION

In a typical die casting process, a molten material is introduced to a shot sleeve of a casting apparatus. The molten material is then forced into a die and cast into a desired object. However, use of a molten material may not be desired or feasible and a semi-solid material is used. Typically, to form a semi-solid material a molten material is electromagnetically stirred and cooled in a separate cooling sleeve. The semi-solid material may also be electromagnetically stirred and cooled in a separate ladle cup. The semi-solid material is then transferred to the shot sleeve before being forced into the die.

Stirring and cooling the semi-solid material in a separate cooling sleeve or ladle cup requires a high level of temperature control of the molten material and the semi-solid material. The properties of the molten material may also require modification prior to mixing and cooling to facilitate the high level of temperature control. Furthermore, stirring and cooling the semi-solid material in a separate cooling sleeve or ladle cup requires that a robot or other automated device be utilized to transfer the semi-solid material to the shot sleeve. Such robots and devices may be extremely expensive and lengthen the cycle time of the casting process. Mechanical issues may also arise with the robot or automated device.

It would be desirable to develop a method and apparatus for forming a semi-solid material in a shot sleeve wherein a handling of the semi-solid material minimized.

SUMMARY OF THE INVENTION

Concordant and congruous with the present invention, a method and apparatus for forming a semi-solid material in a shot sleeve wherein a handling of the semi-solid material minimized, has surprisingly been discovered.

In one embodiment, the casting apparatus comprises a mixing sleeve having a mixing cavity formed therein for receiving a molten material; a shot sleeve having a shot sleeve cavity formed therein, the shot sleeve cavity in fluid communication with the mixing sleeve cavity; an electromagnetic circuit adapted to produce an electromagnetic current for mixing the molten material in the mixing sleeve cavity; and a cooling sleeve disposed adjacent the mixing sleeve, the cooling sleeve causing the molten material in the mixing sleeve cavity to cool as the electromagnetic current causes a mixing of the molten material until the molten material forms a semi-solid material.

In another embodiment, a mold for casting comprises a mixing sleeve having a mixing sleeve cavity formed therein for receiving a molten material; a shot sleeve having a shot sleeve cavity formed therein, the shot sleeve in fluid communication with the mixing sleeve cavity; a means for causing the molten material to flow into the mixing sleeve cavity of the mixing sleeve; an electromagnetic circuit positioned adjacent the mixing sleeve, the electromagnetic circuit adapted to produce an electromagnetic current, for mixing the molten material in the mixing sleeve cavity; and a cooling sleeve disposed adjacent the mixing sleeve, the cooling sleeve causing the molten material in the mixing sleeve cavity to cool as the electromagnetic current causes a mixing of the molten material until the molten material forms a the semi-solid material.

The invention also provides a method of forming a semi-solid material in a shot sleeve cavity comprising the steps of providing a casting apparatus comprising a mixing sleeve having a mixing sleeve cavity formed therein for receiving a molten material therein, a shot sleeve having a shot sleeve cavity formed therein for receiving a semi-solid material therein, a means for causing the molten material to substantially fill the mixing sleeve cavity, an electromagnetic circuit for producing an electromagnetic current for mixing the molten material, and a cooling sleeve; positioning the electromagnetic circuit and the cooling sleeve adjacent at least a portion of the mixing sleeve; introducing the molten material into the casting apparatus; energizing the electromagnetic circuit to produce an electromagnetic current in the molten material in the mixing sleeve cavity, wherein the electromagnetic current causes a mixing of the molten material; and causing the cooling sleeve to cool the molten material as the electromagnetic current mixes the molten material until the semi-solid material is formed.

DESCRIPTION OF THE DRAWINGS

The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:

FIG. 1 is a cross-sectional view of a shot sleeve apparatus according to an embodiment of the invention;

FIG. 2 is a cross-sectional view of the shot sleeve apparatus of FIG. 1 during a pouring of a molten material;

FIG. 3 is a cross-sectional view of the shot sleeve apparatus of FIG. 1 after the molten material has been poured;

FIG. 4 is a cross-sectional view of the shot sleeve apparatus of FIG. 1 during a mixing of the molten material;

FIG. 5 is a cross-sectional view of the shot sleeve apparatus of FIG. 1 during a movement of a semi-solid material into a shot sleeve;

FIG. 6 is a cross-sectional view of the shot sleeve apparatus of FIG. 1 during an injecting of the semi-solid material into a die;

FIG. 7 is a cross-sectional view of the shot sleeve apparatus of FIG. 1 during a removal of a cast object from the die;

FIG. 8 is a cross-sectional view of a shot sleeve apparatus according to another embodiment of the invention;

FIG. 9 is a cross-sectional view of the shot sleeve apparatus of FIG. 8 during a mixing of a molten material.

FIG. 10 is a cross-sectional view of a shot sleeve apparatus according to another embodiment of the invention;

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. In respect of the methods disclosed, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical.

FIG. 1 shows a shot sleeve apparatus 10 including a mixing sleeve 12 forming a mixing sleeve cavity 14, a means for causing 16 a molten material 18 (shown in FIGS. 2-4) to substantially fill the mixing sleeve cavity 14, a cooling sleeve 20, an electromagnetic circuit 22, a gate 24, a thermocouple 26, and a shot sleeve 28 forming a shot sleeve cavity 30. The molten material 18 can be any castable material such as aluminum, for example.

The mixing sleeve 12 forms the mixing sleeve cavity 14 which includes an inlet 32 and an outlet 34. The inlet 32 provides fluid communication between an exterior of the mixing sleeve 12 and the mixing sleeve cavity 14. The outlet 34 provides communication between the mixing sleeve cavity 14 and the shot sleeve cavity 30. The gate 24 is adapted to close the outlet 34. The plunger 16 is slidably disposed in the mixing sleeve cavity 14. In the embodiment shown, the mixing sleeve 12 has a horizontal orientation. It is understood that the mixing sleeve 12 may have a vertical orientation or an angled orientation, as desired.

In the embodiment shown, the means for causing 16 the molten material 18 to substantially fill the mixing sleeve cavity 14 is a plunger 36. The plunger 36 includes a rod 38 and a body 39 having a tip 40. The tip 40 of the plunger 36 is configured such that it may be slidably positioned in the mixing sleeve cavity 14 and the shot sleeve cavity 30. The tip 40 is adapted to form a seal with an inner wall 42 of the mixing sleeve 12 and an inner wall 44 of the shot sleeve 28. It is understood that the means for causing 16 the molten material 18 to substantially fill the mixing sleeve cavity 14 may be any device capable of causing the molten material 18 to fill the mixing sleeve cavity 14, as desired.

A cooling sleeve cavity (not shown) is formed by the cooling sleeve 20. The cooling sleeve 20 contains a fluid (not shown) and is positioned between the electromagnetic circuit 22 and a portion of the mixing sleeve 12. It is understood that the cooling sleeve 20 may be positioned anywhere on the shot sleeve apparatus 10, such as between the electromagnetic circuit 22 and the portion of the mixing sleeve 12 or adjacent a portion of the shot sleeve 28, as desired. The configuration of the cooling sleeve 20 used depends on the size, shape, surface area, and wall thickness of the mixing sleeve 14 and the shot sleeve 28. Further, the configuration of the cooling sleeve 20 used also depends on the molten material 18 used and a desired cooling rate of the molten material 18. In the embodiment shown, the fluid is water. It is understood that other fluids may be used such as a water-glycol mix or any other fluid, or multipurpose solid-liquid convection medium, for example. The fluid used depends on the desired cooling rate of the molten material 18, the properties of the fluid, and other similar factors.

The electromagnetic circuit 22 is adapted to produce an electromagnetic current as indicated by the arrow A in FIG. 4. It is understood that the electromagnetic circuit 22 may be any electromagnet such as a solenoid or toroid, for example. As shown, the electromagnetic circuit 22 is positioned immediately adjacent the cooling sleeve 20. It is understood that the electromagnetic circuit 22 may be positioned anywhere on the shot sleeve apparatus 10, where the electromagnetic current flows toward the molten material 18 in the mixing sleeve cavity 14.

The gate 24 is disposed between the mixing sleeve cavity 14 and shot sleeve cavity 30 to militate against the flow of molten material 18 and semi-sold material 36 from the mixing sleeve cavity 14 to the shot sleeve cavity 30. As shown, the gate 24 is adapted to be slidably removed from a position between the mixing sleeve cavity 14 and the shot sleeve cavity 30. Other structures may be used such as a valve, for example, to selectively militate against flow and permit flow between the mixing sleeve cavity 14 and the shot sleeve cavity 30. It is understood that the gate 24 may be produced from any conventional material, as desired.

The thermocouple 26 is disposed in the mixing sleeve 12 and extends into the mixing sleeve cavity 14. It is understood that the thermocouple 26 may be disposed anywhere on the apparatus 10 as desired, such as partially disposed in the mixing sleeve cavity 14, partially disposed in the shot sleeve cavity 30, and coupled to the gate 24, for example. The thermocouple 26 may be any conventional thermocouple known in the art.

The shot sleeve 28 includes an inlet 48 and an outlet 50. The inlet 48 is in communication with the outlet 34 of the mixing sleeve 12. The gate 24 is disposed between the outlet 34 of the mixing sleeve 12 and the inlet 48 of the shot sleeve 28. The second outlet 50 is in fluid communication with a die cavity 52 formed in a cover die 54 and an ejector die 56. The die cavity 52 may have any shape, as desired, to form a desired cast object. In the embodiment shown, the shot sleeve 28 has a horizontal orientation linearly aligned with the mixing sleeve 12. It is understood that the shot sleeve 28 may have a vertical orientation or an angled orientation, or other orientation, as desired. Although the mixing sleeve 12 and the shot sleeve 28 are aligned linearly in the embodiment shown, it is understood that other configurations can be used as desired.

In use, the molten material 18 is produced in a furnace (not shown) or other heating device. Typically, the molten material 18 is then introduced to the shot sleeve apparatus 10. The molten material 18 is poured from a ladle 19 in the mixing sleeve cavity 14 of the mixing sleeve 12 through the first inlet 32, as shown in FIGS. 2 and 3. It is understood that other structures can be used to introduce the molten material 18 into the mixing sleeve cavity 14.

As shown in FIG. 4, the plunger 36 is then caused to move to a position which causes the molten material 18 to substantially fill a portion of the mixing sleeve cavity 14. The plunger 36 militates against the flow of the molten material 18 or the semi-solid material 46 toward the rod 38 of the plunger 36. It is understood that the plunger 36 may also be utilized to transfer the semi-solid material 46 from the mixing sleeve cavity 14 to the shot sleeve cavity 30 and a die cavity 52, as desired. Once the portion of the mixing sleeve cavity 14 has been substantially filled with the molten material 18, the electromagnetic circuit 22 is energized to provide the electromagnetic current A to the molten material 18. The electromagnetic current causes a mixing of the molten material 18 to occur in the mixing sleeve cavity 14. The amount of electromagnetic current A required to be produced by the electromagnetic circuit 22 depends on the amount of molten material 18 in the portion of the mixing sleeve cavity 14, the material properties of the molten material 18, an amount of mixing desired, and the rate at which the molten material 18 is to be mixed. Concurrent with the energization of electromagnetic circuit 22, the fluid is caused to flow to the cooling sleeve 20. The fluid in the cooling sleeve cavity of the cooling sleeve 20 causes the molten material 18 in the mixing sleeve 12 to begin cooling. A temperature of the molten material 18 in the mixing sleeve 12 is measured by the thermocouple 26. The simultaneous mixing and cooling of the molten material 18 in the mixing sleeve 12 causes the material properties of the molten material 18 to change until the semi-solid material 46 is formed. The mixing and cooling of the molten material 18 continues until a desired temperature is reached. The electromagnetic circuit 22 is then de-energized to stop the mixing. The desired temperature is determined based on the properties of the molten material 18 used and the desired properties of the semi-solid material 46 to be formed. It is understood that the cooling step and mixing step may occur at the substantially same time or at different times, as desired.

After the desired temperature is reached and the electromagnetic circuit 22 is de-energized, the gate 24 and the thermocouple 26 are retracted and the plunger 36 is caused to slidingly move in the mixing sleeve cavity 14 and cause the semi-solid material 46 to move into the shot sleeve cavity 30, as shown in FIG. 5. While the plunger 36 is positioned in the shot sleeve 28, a control system (not shown) adjusts the speed and pressure of the plunger 36 to inject the semi-solid material 46 into the die cavity 52, as shown in FIG. 6. The control system may be any conventional system including devices, such as a timer, a switch, and a thermocouple, for example.

As shown in FIG. 7, once the semi-solid material 46 in the die cavity 52 has solidified and cooled to a desired temperature, the ejector die 56 is opened and the desired cast object can be removed therefrom. It is understood that the ejector die 56 may be opened using an automated device as known in the art, or the ejector die 56 may be opened manually. Once the desired cast object is removed from the die cavity 52, typical open dwell activities such as cleaning and machining of the desired cast object can be conducted.

FIG. 8 shows a shot sleeve apparatus 60 according to another embodiment of the invention including a plunger 62, a mixing sleeve 64 forming a mixing sleeve cavity 66, a means for causing (not shown) a molten material 68 to substantially fill the mixing sleeve cavity 66, a cooling sleeve 70, an electromagnetic circuit 72, a thermocouple 74, and a shot sleeve 76 forming a shot sleeve cavity 78.

The plunger 62 includes a rod 80 and a body 81 having a tip 82. The tip 82 of the plunger 62 is sized such that it may be slidably positioned in the mixing sleeve cavity 66 and the shot sleeve cavity 78. The tip 82 is adapted to form a seal with an inner wall 84 of the mixing sleeve 64 and an inner wall 86 of the shot sleeve 76.

In the embodiment shown, the means for causing the molten material 68 to substantially fill the mixing sleeve cavity 66 is gravity. It is understood that the means for causing the molten material 68 to substantially fill the mixing sleeve cavity 66 may be any device or force capable of causing the molten material 68 to fill the mixing sleeve cavity 66, such as a plunger, for example. In the embodiment shown, the mixing sleeve 64 has an angled orientation. It is understood that the mixing sleeve 64 may have a vertical orientation or a horizontal orientation, as desired.

The cooling sleeve 70 forms a cooling sleeve cavity (not shown) which is in fluid communication with a fluid (not shown). As shown, the cooling sleeve 70 is positioned between the electromagnetic circuit 72 and a portion of the mixing sleeve 64. It is understood that the cooling sleeve 70 may be positioned anywhere on the shot sleeve apparatus 60, such as between the electromagnetic circuit 72 and the portion of the mixing sleeve 64 or adjacent a portion of the shot sleeve 76, as desired. The configuration of the cooling sleeve 70 used depends on the size, shape, surface area, and wall thickness of the mixing sleeve 64 and the shot sleeve 76. Further, the configuration of the cooling sleeve 70 used also depends on the molten material 68 used and a desired cooling rate of the molten material 68. In the embodiment shown, the fluid is water. It is understood that other fluids may be used such as a water-glycol mix or any other fluid, or multipurpose solid-liquid convection medium, for example. The fluid used depends on the desired cooling rate of the molten material 68, the properties of the fluid, and other similar factors.

The electromagnetic circuit 72 is adapted to produce an electromagnetic current as indicated by the arrow B in FIG. 9. It is understood that the electromagnetic circuit 72 may be any electromagnet such as a solenoid or toroid, for example. As shown, the electromagnetic circuit 72 is positioned adjacent the cooling sleeve 70. It is understood that the electromagnetic circuit 72 may be positioned anywhere on the shot sleeve apparatus 60, where the electromagnetic current flows toward the molten material 68 in the mixing sleeve cavity 66.

The thermocouple 74 is disposed in the mixing sleeve 64 and extends into the mixing sleeve cavity 66. It is understood that the thermocouple 74 may be disposed anywhere on the apparatus 60 as desired, such as partially disposed in the mixing sleeve cavity 66 and partially disposed in the shot sleeve cavity 78, for example. The thermocouple 74 may be any conventional thermocouple known in the art.

The shot sleeve 76 includes an inlet 88. The inlet 88 is in fluid communication with the shot sleeve cavity 78 and the mixing sleeve cavity 66. The first inlet 88 is also in fluid communication with a die cavity 90 formed by a cover die 92 and an ejector die 94 when the ejector die 94 is positioned adjacent the cover die 92 and shot sleeve 76. The die cavity 90 may have any shape, as desired, to form a desired cast object. In the embodiment shown, the shot sleeve 76 has an angled orientation with respect to horizontal. It is understood that the shot sleeve 76 may have a horizontal orientation or a vertical orientation or other orientation, as desired. Although the mixing sleeve 64 and the shot sleeve 76 are aligned linearly in the embodiment shown, it is understood that other configurations can be used as desired.

In use, the molten material 68 is produced in a furnace (not shown) or other heating device. The molten material 68 is then introduced to the shot sleeve apparatus 60. The molten material 68 is poured from a ladle 69 through the inlet 88, as shown in FIG. 8. The means for causing the molten material 68 to substantially fill the mixing sleeve cavity 66 in the embodiment shown is gravity. The molten material 68 flows to the mixing sleeve cavity 66 and substantially fills a portion thereof.

Once the portion of the mixing sleeve cavity 66 has been substantially filled with the molten material 68, the electromagnetic circuit 72 is caused to provide the electromagnetic current B to the molten material 68. The electromagnetic current causes a mixing of the molten material 68 to occur in the portion of the mixing sleeve cavity 66. The amount of electromagnetic current B required to be produced by the electromagnetic circuit 72 depends on the amount of molten material 68 in the portion of the mixing sleeve cavity 66, the material properties of the molten material 68, an amount of mixing desired, and the rate at which the molten material 68 is to be mixed. Concurrent with the energization of the electromagnetic circuit 72, the fluid is caused to flow through the cooling sleeve 70. The fluid in the cooling sleeve cavity of the cooling sleeve 70 causes the molten material 68 in the mixing sleeve 64 to begin cooling. A temperature of the molten material 68 in the mixing sleeve is measured by the thermocouple 74. The simultaneous mixing and cooling the molten material 68 in the mixing sleeve 64 causes the material properties of the molten material 68 to change until a semi-solid material (not shown) is formed. The mixing and cooling of the molten material 68 continues until a desired temperature is reached. The electromagnetic circuit 72 is then de-energized to stop the mixing. The desired temperature is determined based on the properties of the molten material 68 used and the desired properties of the semi-solid material to be formed. It is understood that the cooling step and mixing step may occur at the substantially same time or at different times, as desired.

After the desired temperature is reached and the electromagnetic circuit 72 is de-energized, the thermocouple 74 is retracted, and the plunger 62 is caused to slidingly move in the mixing sleeve cavity 66 and cause the semi-solid material to move through the mixing sleeve cavity 66 and into the shot sleeve cavity 78 as described for FIGS. 1 through 7. While the plunger 62 is positioned in the shot sleeve 76, a control system (not shown) adjusts the speed and pressure of the plunger 62 to inject the semi-solid material into the die cavity 90. The control system may be any conventional system including devices, such as a timer, a switch, and a thermocouple, for example.

Once the semi-solid material in the die cavity 90 has solidified and cooled to a desired temperature, the ejector die 94 is opened and the desired cast object can be removed. It is understood that the ejector die 94 may be opened using an automated device as known in the art, or the ejector die 94 may be opened manually. Once the desired cast object is removed from the die cavity 90 typical open dwell activities such as cleaning and machining of the desired cast object, for example can be conducted.

FIG. 10 shows a shot sleeve apparatus 60′ according to another embodiment of the invention. Repeated structure from FIGS. 8 and 9 have the same reference numeral and a prime (′) for clarity. A description and use thereof is not repeated. The molten material 68′ may be introduced into the shot sleeve apparatus 60′ with the ladle 69′ or with a metal pump (not shown), or a vacuum sucker tube (not shown).

From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions. 

1. A casting apparatus comprising: a mixing sleeve having a mixing sleeve cavity formed therein for receiving a molten material; a shot sleeve having a shot sleeve cavity; formed therein, the shot sleeve cavity in fluid communication with the mixing sleeve cavity; an electromagnetic circuit adapted to produce an electromagnetic current (A, B) for mixing the molten material in the mixing sleeve cavity; and a cooling sleeve disposed adjacent said mixing sleeve, said cooling sleeve causing the molten material in the mixing sleeve cavity to cool as the electromagnetic current (A, B) causes a mixing of the molten material until the molten material forms a semi-solid material.
 2. The apparatus of claim 1, further comprising a means for causing the molten material to flow into the mixing sleeve cavity of said mixing sleeve.
 3. The apparatus of claim 2, wherein said means for causing the molten material to substantially fill the mixing sleeve cavity is a plunger.
 4. The apparatus of claim 2, wherein said means for causing the molten material to substantially fill the mixing sleeve cavity is gravity.
 5. The apparatus of claim 1, further comprising a gate for militating against flow of the molten material from the mixing sleeve cavity to the shot sleeve cavity.
 6. The apparatus of claim 1, wherein said shot sleeve is substantially linearly aligned with said mixing sleeve.
 7. The apparatus of claim 6, wherein said shot sleeve and said mixing sleeve are disposed in one of a vertical orientation, a horizontal orientation, and an angled orientation with respect to horizontal.
 8. The apparatus of claim 1, wherein said cooling sleeve is positioned between said mixing sleeve and said electromagnetic circuit.
 9. The apparatus of claim 1, further comprising a thermocouple for measuring a temperature of the molten material and the semi-solid material in the mixing sleeve cavity.
 10. The apparatus of claim 1, wherein said mixing sleeve has an inlet formed therein.
 11. A casting apparatus comprising: a mixing sleeve having a mixing sleeve cavity formed therein for receiving a molten material; a shot sleeve having a shot sleeve cavity formed therein, the shot sleeve in fluid communication with the mixing sleeve cavity; a means for causing the molten material to flow into the mixing sleeve cavity of said mixing sleeve; an electromagnetic circuit positioned adjacent said mixing sleeve, said electromagnetic circuit adapted to produce an electromagnetic current (A, B), for mixing the molten material in the mixing sleeve cavity; and a cooling sleeve disposed adjacent said mixing sleeve. said cooling sleeve causing the molten material in the mixing sleeve cavity to cool as the electromagnetic current (A, B) causes a mixing of the molten material until the molten material forms a semi-solid material.
 12. The apparatus of claim 11, wherein said means for causing the molten material to substantially fill the mixing sleeve cavity is a plunger.
 13. The apparatus of claim 11, wherein said means for causing the molten material to substantially fill the mixing sleeve cavity is gravity.
 14. The apparatus of claim 11, further comprising a gate for militating against flow of the molten material from flowing from the mixing sleeve to the shot sleeve cavity.
 15. The apparatus of claim 11, wherein said shot sleeve is substantially linearly aligned with said mixing sleeve.
 16. The apparatus of claim 15, wherein said shot sleeve and said mixing sleeve are disposed in one of a vertical orientation, a horizontal orientation, and an angled orientation with respect to horizontal.
 17. The apparatus of claim 11, further comprising a thermocouple for measuring a temperature of the molten material and the semi-solid material in the mixing sleeve cavity.
 18. A method of forming a semi-solid material in a shot sleeve cavity comprising the steps of: providing a casting apparatus comprising a mixing sleeve having a mixing sleeve cavity formed therein for receiving a molten material therein, a shot sleeve having a shot sleeve cavity formed therein for receiving a semi-solid material therein, a means for causing the molten material to substantially fill the mixing sleeve cavity, an electromagnetic circuit for producing an electromagnetic current (A, B) for mixing the molten material, and a cooling sleeve; positioning the electromagnetic circuit and the cooling sleeve adjacent at least a portion of the mixing sleeve; introducing the molten material into the casting apparatus; energizing the electromagnetic circuit to produce an electromagnetic current (A, B) in the molten material in the mixing sleeve cavity, wherein the electromagnetic current (A, B) causes a mixing of the molten material; and causing the cooling sleeve to cool the molten material as the electromagnetic current (A, B) mixes the molten material until the semi-solid material is formed.
 19. The method of claim 18, further providing a gate for militating against a flow of the molten material from the mixing sleeve to the shot sleeve cavity.
 20. The method of claim 18, wherein the means for causing the molten material to substantially fill the mixing sleeve cavity is one of a plunger and gravity. 